A search has begun to locate the original film footage of man's first steps on the Moon.

The footage of the Apollo 11 crew's landing on the Moon is one of 20th Century's most important artefacts.

The tapes are believed to be stored somewhere in the archive at Nasa's Goddard Space Flight Center, Maryland.

But as many of those involved in the archiving of the original tapes moved on, retired or passed away their location has been lost.

The footage seen by people around the world has been compared to a photocopy of a photocopy, according to the Daily Telegraph newspaper.

It came from a camera that had been pointed at a black-and-white monitor. The astronauts actually beamed higher-quality footage back to Earth -seen by a small number of people at three tracking stations.

But this had already been stripped of much of its detail. To make sure the transmission would make it back to Earth, the images sent back by the astronauts were recorded at 10 frames per second (fps), and had to be converted to 60fps in order to be broadcast.

In the process, much of the detail was lost.

Eighty-one-year-old Stan Lebar was in charge of the images from Apollo 11. He said what he saw was so blurred he initially thought something had gone wrong.

"We thought there had been a problem getting the converter to work properly," he said.

"What was broadcast to the world was nowhere near as good as what was received," said John Sarkissian, of the CSIRO Parkes Observatory in Australia, one of the three tracking stations that taped the original footage before sending it on to Houston in converted form.

Although these tapes did not match the standard of normal TV transmissions, they would still be better than the video we have today, especially if processed using digital technology. A coalition of scientists and Nasa veterans - including Mr Lebar and Mr Sarkissian - is now hunting through Nasa's archives.

The tapes appear to have been sent to the US National Archives, before being returned to Nasa, which stored them at its Goddard Space Flight Center in Maryland.

"I just think this is what happens when you have a large government bureaucracy that functions for decade after decade," said Keith Cowing, editor of the website Nasa Watch.

"It's not malicious or intentional, but I think it's unfortunate that Nasa doesn't have maybe just one more person whose job it is to look back at its history."

A Nasa spokesman said: "We're trying to track them down through the paperwork created at the time - but it's 35 years ago, so it's a challenge."